Double valve

ABSTRACT

The invention relates to a double valve with a valve housing ( 1 ), for housing two double-headed actuators ( 30, 31 ), whereby the double head actuators have differing head diameters ( 12, 13 ) and the flow of a fluid through the both actuators ( 30, 31 ) in the valve housing ( 1 ) is identical. The valve housing ( 1 ) is of one-piece design and a drive function for both actuators ( 30, 31 ) is not connected to the inner volume of the valve housing ( 1 ) with fluid flowing therein.

The present invention concerns a double valve as set forth in theclassifying portion of claim 1.

Double-seat valves are known for example from DE 31 46 590, describingdouble-seat valves in which the internal diameters of the valve seatsare relatively greatly different. As a result, when pressure is appliedbetween the valve disks, the opening force of the upper valve disk whichis of a larger internal diameter is greater than the closing force atthe lower valve disk.

In terms of gas applications, a multiple actuating device has gainedgeneral acceptance on a broad basis as a safety and regulating unitupstream of the heat producer, for example a gas fan burner, because inone unit it contains the required safety functions—at least two safetyshut-off valves in series—or it permits an additional function to beadded on. Besides the economic advantages involved, this compactstructure affords a high guarantee in respect of the safety andmonitoring functions for the user in particular in regard to the safetyregulations to be observed.

Those multiple actuating devices are to be found in gas applicationsboth in the lowest and also in the highest output range. Even if safetyfunctions are combined with regulating or control functions the actuatorand the prescribed closing spring remain the determining componentswhich ensure reliable closure.

If the single-disk actuators for the two valves and the regulator arethe characterising structural feature in relation to the small multipleactuating devices for output values<50 kW, it is clearly the double-diskactuators which determine the structural configurations of the housings,up into the high output levels. Particularly with nominal widths ofgreater than DN 50 with the same housing length and without a loss ofthrough-flow the double actuator makes it possible to install twoshut-off valves.

Double solenoid valves are known which cover the nominal width range ofDN 40 to DN 125 and which are equipped with solenoid drives. Also knownare double-disk actuators, comprising however single valve housings,which can be assembled together to form multiple actuating devices. Thatprovides that the afflux flow to the two actuators is identical, whichis not the case with housing types from other manufacturers. If forexample housings of that kind are produced in the form of die castingswithout insert cores, then, as considered in the through-flow direction,they are of a center-symmetrical design configuration, with theconsequence that the gas flows to the two double-disk actuators oncefrom the inside and once from the outside, which, depending on therespective nature of the two disk diameters on the double-disk actuator,results on the one hand in a force having an opening action and on theother hand a force having a closing action, due to the gas intakepressure.

The object of the present invention is to provide a double valve havinga valve housing for two actuators, which avoids those disadvantages.

According to the invention the specified object is attained by thefeatures recited in the independent claims.

Therefore the core of the invention is that the valve housing is of aone-piece configuration and that a drive function of the two actuatorsis not connected to the internal space of the valve housing, throughwhich space the fluid flows.

In order to provide the same conditions for a gas intake pressure forceacting in a closing mode for both actuators in the case of one-piecehousings, it is necessary to have recourse to casting production withinsert cores. In contrast to the center-symmetrical valve housings thenew housing types have only one through-flow direction, in relation tothe actuator.

Those housings afford the greatest advantage when the drives used are inthe form of complete functional units which, besides the pure functionof automatically opening and autonomously implementing closing, can alsotake over regulating functions. If in addition the valve housing initself is designed in the form of a safety component which involvessealing integrity in the closed position in the through-flow directionand outwardly, all drive and regulating functions can be added on to theactuator axis at the intake and/or exit side.

That deliberate separation of the gas space of the valve housing and thedrives which thus operate in the ambient atmosphere affords greatadvantages which increase with an increasing nominal width, from thepoint of view of the installer on site, due to the saving in weight andhandling of the smaller valve volume upon installation in the conduit.

A replacement of or a change in drive functions is facilitated incomparison with the known valves as it is not necessary to interveneinto the gas space, so that a check in respect of sealing integritywhich is otherwise prescribed when changing the drive is no longerinvolved.

The entire logistics can be simplified if the user himself determinesthe nature and the location for the drive, without for that purposepreviously ordering a complete assembly from the manufacturer. Thuspneumatically or hydraulically driven servo motors with additionalfunctions such as pilot regulators, equal-pressure regulators,zero-pressure regulators, reference value regulators or compositeregulators are nowadays in use as standard drive configurations. It isalso found here that the modular structure permits a highly flexibledesign configuration for the multiple actuating device. If then thosedrives are also suitable for the entire range of valve housings, thatattains a very high level of logistic advantages.

Further advantageous configurations of the invention are set forth inthe appendant claims.

Some preferred embodiments of the apparatus according to the inventionand the method according to the invention are described in greaterdetail by means of the accompanying drawings in which:

FIG. 1 is a view in longitudinal section of the valve housing accordingto the invention for the construction of a multiple actuating device,

FIG. 2 shows a side view of the valve housing with a flange-mounteduniversal adaptor, and

FIG. 3 shows a side view of the valve housing with a flange-mountedignition gas connection flange.

The valve housing 1 which is shown in FIG. 1 and through which fluidflows in the direction marked by the arrow 2 forms three spaces. Theintake space which is subjected to the action of the intake pressureP_(e), the central space which is disposed between the two actuators 30,31 and in which in operation the central space pressure P_(m) obtains,and the exit space downstream of the actuator 31 on the exit side, inwhich the exit pressure P_(a) or the burner pressure fed to the burneris measured.

The valve housing 1 is characterised by the two axes 10 of thedouble-disk actuators 30, 31, wherein each axis has a large valve seatdiameter 3 and a small valve seat diameter 4 in such a way that thesmall disk 12 fits through the internal diameter of the seat 4. Thediameter difference between the large and the small valve seat diametersforms a circular ring surface which, by virtue of the intake pressure(or central space pressure), produces a force for closing the actuator.That force is so divided by virtually flexurally slack subdivision ofthe large disk 13 that the valve seats 3 and 4 involve approximately thesame closing force component due to the respectively applied gaspressure. To comply with the check in respect of sealing integrity inthe counter-flow direction, as is prescribed for gas safety valves, twoclosing springs 7 are installed for each actuator axis in order toproduce the necessary closing pressure at the valve seat. The disks areprovided at the seat side with a sealing material vulcanised thereto.

The arrows 11 illustrate the opening direction for the drives. Thearrangement requires drives with a pushing force which acts on thethrust rod 14, in which case then the positively engaging elements 16transmit the force to the small disk 12. The force is transmitted by wayof the sleeve 15 to the large disk 13 which is supported on the closingspring pack 7. The thrust rod 14 is guided in the mounting locations 6and 8 which are far apart so that the double-disk actuator involves thesmallest amount of wobble in relation to the valve seats. The mountinglocation 6 additionally has sealing elements in order to ensureatmospheric sealing integrity of the valve housing.

The housing covers 9 close the valve housing upwardly and the two covers9 permit installation of the actuators-and the spring packs on thebottom side of the valve housing. All covers are sealed off relative tothe valve housing by static seals (not shown).

A sieve filter fitted in the intake of the valve housing is intended toprevent the introduction of relatively coarse impurities which caninfluence operation of the valve.

It must be possible to monitor a gas safety and regulating system, andthis is substantially improved by the direct attachment of testingdevices to the valve housing of the multiple actuating device.

The universal flange 18 shown in FIG. 2 takes account of thoserequirements insofar as two pressure monitors can be mounted on thefront side of the flange, wherein one can monitor the gas intakepressure (safeguard against deficiency of gas) by way of the gasconnection 21 and the other can monitor the central space pressure byway of one of the two connections 20. The arrangement also provides fordirect mounting of a valve testing system (sealing integrity control inrespect of the closed actuators) by way of the connection 21 and theadjacent connection 20.

If a valve testing device is fitted, then, for the attachment of a gaspressure monitor for example for monitoring for an absence of gas, itmust be switched to one of the two side surfaces 22.

The universal flange is so designed that monitoring devices from variousmanufacturers can be fitted. The exit pressure or the burner pressurecan be taken off and/or monitored at the pressure measuring connection23.

A flange is fixed to the valve housing opposite the universal flange inFIG. 3, with the same fixing pattern 19 (one of the four fixing screwsis identified), the flange permitting the connection of an ignition gasconduit to the burner. The ignition gas flange 24 forms a connectionbetween the central space of the valve housing and the ignition gasvalve by way of a gas conduit which is to be screwed in thescrewthreaded connection 25. The screwthreaded connection which isclosed by a plug 26 is provided as a pulse connection for a drive withregulator function, the drive being placed on the intake-side actuatoraxis.

Depending on whether the situation involves a left-hand or a right-handgas line the universal flange can be exchanged for the ignition gasflange. Both the universal flange and also the ignition gas flange areadopted unchanged for the entire product family.

It will be appreciated that the invention is not limited to theembodiments described and illustrated.

1. A double valve comprising a valve housing (1) for receiving twoserially connected double-disk actuators (30, 31), wherein thedouble-disk actuators have different disk diameters (12, 13) and theafflux flow by a fluid to the two actuators (30, 31) in the valvehousing (1) is identical, characterised in that the valve housing (1) isof a one-piece configuration and that a drive function of the twoactuators (30, 31) is not connected to the internal space of the valvehousing (1), through which space the fluid flows.
 2. A double valve asset forth in claim 1 characterised in that the drive function of the twodouble-disk actuators (30, 31) is effected from the same side of thevalve housing (1).
 3. A double valve as set forth in claim 1characterised in that the drive function of the two double-diskactuators (30, 31) is flange-mounted to the valve housing (1).
 4. Adouble valve as set forth in claim 1 characterised in that the valvehousing is sealingly closed by covers (9) on the drive side and bycovers (5) on the underside.
 5. A double valve as set forth in claim 1characterised in that at the outside the valve housing (1) is of such aconfiguration that at least one flange (18, 24) can be mounted.
 6. Adouble valve as set forth in claim 5 characterised in that the flange isa universal flange (18) or an ignition gas flange (24).
 7. A doublevalve as set forth in claim 6 characterised in that a universal flange(18) and an ignition gas flange (24) are arranged at the outside of thevalve housing (1).
 8. A double valve as set forth in claim 7characterised in that depending on the respective direction ofinstallation of the valve housing (1) the universal flange (18) and theignition gas flange (24) are arranged on different sides of the valvehousing (1).